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From: David Howells <dhowells@redhat.com>
In-Reply-To: <20130403144857.22351.67546.stgit@rabbit.intern.cm-ag>
References: <20130403144857.22351.67546.stgit@rabbit.intern.cm-ag>
To: Max Kellermann <mk@cm4all.com>
Cc: dhowells@redhat.com, linux-cachefs@redhat.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fscache: extended "dying" check before emitting EV_INVALIDATE
Date: Tue, 23 Apr 2013 17:57:46 +0100
Message-ID: <5827.1366736266@warthog.procyon.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 963
Lines: 21

Max Kellermann <mk@cm4all.com> wrote:

> Before emitting an FSCACHE_OBJECT_EV_INVALIDATE event, the function
> __fscache_invalidate() checks whether the fscache_object is currently
> "dying".  This checks only the current state, not the queued events
> that will very soon lead to the object's death.

This should not be a problem, I think.  EV_RETIRE and EV_RELEASE should only be
set by fscache_relinquish_cookie().  If you (the netfs) call that to dispose of
a cookie to fscache, you shouldn't thereafter be calling fscache_invalidate()
on it.  The only case in which __fscache_invalidate() should see a dying object
is if the caching backend withdraws it (ie. EV_WITHDRAW is set).

Do you have a backtrace?

David
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